Downrigger fishing is a technique which is common to both commercial fishermen and sports fishermen. The downrigger technique is used to troll for fish which swim at great depths, sometimes 100 feet or more. In this technique a downrigger, which is a line or cable with a heavy weight attached to it, is suspended from a boat to a predetermined depth. One or more fishing lines with baited hooks or lures are releasably attached to the weight or at different depths along the downrigger line. The heavy weight holds the fishing lines at an appropriate depth for catching the fish.
When a fish takes one of the hooks, the fishing line is released from the downrigger so that the fish can be landed without fighting against the heavy weight of the downrigger. A number of releasable clips have been devised for attaching fishing lines to a downrigger. Examples of these include U.S. Pat. Nos. 3,816,954; 3,874,110; 3,925,920; 4,065,869; 4,069,611; 4,513,524 and 4,942,690. Any one of these prior art devices can be used with the present invention, therefore, the specifications of these patents are hereby incorporated by reference in their entirety.
A number of hydrodynamic planing devices have been suggested for use in downrigger fishing. All of these prior art devices suffer from one or more deficiencies which have limited their popularity for downrigger fishing. U.S. Pat. No. 3,738,047 for a Fish Line Carrier describes a device which uses hydrodynamic force to carry a fishing line downward along a downrigger line. The device has a friction clamp which holds the fishing line so that it will be released when the hook is struck by a fish. This device has no mechanism to carry it back up the downrigger line when the fishing line is released. Consequently, each time a fish is caught, the fisherman must add a new fish line carrier to the downrigger line if he wants to avoid reeling up the downrigger each time. Eventually, several line carriers will be stacked up on the downrigger weight. The added weight and the hydrodynamic force of the stacked carriers will make it more difficult to reel up the downrigger line.
U.S. Pat. No. 3,839,813 for a Down Rigger Diving Plane describes another device which uses hydrodynamic force to carry a fishing line downward along a downrigger line. To avoid the disadvantage of adding multiple line carriers to the downrigger line like the device above, this device is made so that it releases from the downrigger line and stays attached to the fishing line when a fish strikes the hook. The device is then reeled in with the fish, and it can be reattached to the downrigger line when the hook is rebaited and lowered again. This approach has the disadvantage that the hydrodynamic resistance of the device on the fishing line reduces the sport and excitement of "playing" the fish while landing it.
U.S. Pat. No. 4,212,127 for a Power Plane For Transporting Fishing Line describes an improved downrigger fishing device which not only uses hydrodynamic force to carry a fishing line downward along a downrigger line, but when the fishing line is released, the power plane changes attitude so that the hydrodynamic force will carry the device back up the downrigger line. This improvement allows the device to be used multiple times so that many fish can be caught without the need to reel in the downrigger or to add several line carriers. However, even this device has a number of disadvantages that have limited its popularity. The device, as described in the patent, is complicated to use and complicated to manufacture. In addition, the device is not responsive to the user. Once the device has been set up and released, it will continue to plane downward until the fishing line is released. The user cannot retrieve the device except by pulling on the fishing line hard enough to detach it from the device so that it will begin to rise up on its own. This means that anytime the fisherman wants to check the bait, he or she must pull the fishing line free from the power plane, reel it in, then reset the power plane so that it will carry the line back down again.